Traditional packers comprised of a sealing element having anti-extrusion rings on both upper and lower ends and a series of slips above or/and below the sealing element. Typically a setting tool would be run with the packer to set it. The setting could be accomplished hydraulically due to relative movement created by the setting tool when subjected to applied pressure. This relative movement would cause the slips to ride up cones and extend into the surrounding tubular. At the same time, the sealing element would be compressed into sealing contact with the surrounding tubular. The set could be held by a body lock ring, which would prevent reversal of the relative movement, which caused the packer to set in the first instance.
As an alternative to pressure through the tubing to the setting tool to cause the packer to set, another alternative was to run the packer in on wire line with a known electrically operated setting tool such as an E-4 made by Baker Oil Tools. In this application, a signal fires the E-4 causing the requisite relative movement for setting the packer. Some of these designs were retrievable. A retrieving tool could be run into the set packer and release the grip of the lock ring so as to allow a stretching out of the slips back down their respective cone and for the sealing element to expand longitudinally while contracting radially so that the packer could be removed from the well.
In the past, sealing has been suggested between an inner and an outer tubular with a seal material in between. That technique, illustrated in U.S. Pat. No. 6,098,717, required the outer tubular or casing to be expanded elastically and the inner tubular to be expanded plastically. The sealing force arose from the elastic recovery of the casing being greater than the elastic recovery of the inner tubular, thus putting a net compressive force on the inner tubular and the seal. Other expansion techniques, described in U.S. Pat. Nos. 5,348,095; 5,366,012; and 5,667,011 simply related to expansion of slotted tubulars, serving as a liner in open hole, as a completion technique. U.S. Pat. No. 4,069,573 illustrates the use of expansion to form a tubular casing patch.
The present invention relates to construction features and methods of employing packers that can be expanded into sealing position. The surrounding tubular does not need to be expanded to set the packer of the present invention. Rather, an anchor such as slips is used to support the expanded sealing element and hold it in a set position. Preferably, existing setting tools, with minor modifications can be used to expand the packer of the present invention. Similarly releasing tools can be employed to remove the packer from its set position. The running string can be exposed to lower pressures than the packer through the use of pressure intensifiers. The expansion force can be pinpointed to the area of the packer, thus avoiding subjecting the formation or the running string to undue pressures during setting of the packer. Alternatively, the inner tubular may simply be an anchor for another tool or a liner string. The anchoring can be ridges on the exterior of the inner tubing directly or on a ring mounted over the inner tubular being expanded. The ring can be slotted to reduce the required expansion force. The slips are retained to the mandrel by undulating mating surfaces. The grip area is enlarged to reduce stress on the tubular. Features are included to help hold the set on shifting load conditions and to augment the applied force on the sealing element. A variety of potential applications are illustrated.
The setting tool can be delivered through tubing on slick line or wire line or run into the well on rigid or coiled tubing or wire line, among other techniques. The release tool can be likewise delivered and when actuated, stretches the packer or anchor out so that it can be removed from the wellbore. Conventional packers, that have their set held by lock rings, can be released with the present invention, by literally pushing the body apart as opposed to cutting it downhole as illustrated in U.S. Pat. No. 5,720,343.
These and other advantages of the present invention will be more readily understood from a review of the description of the preferred embodiment, which appears below.